RailsAdmin is an awesome gem when you want to build a not-so-much custom admin panel. Unfortunately it’s not mentioned in documentation (or at least I couldn’t find it) how to use it with HTTP Basic authentication. Here is an example of how to do this (put this in your config/initializers/rails_admin.rb file):

RailsAdmin.config do |config|
config.authenticate_with do
authenticate_or_request_with_http_basic do |username, password|
username == 'user' &&
password == 'password'
end
end
# Other config stuff should go here
end

You should also use gem like SettingsLogic for storing credentials like this:

RailsAdmin.config do |config|
config.authenticate_with do
authenticate_or_request_with_http_basic do |username, password|
username == System::Settings.admin.username &&
password == System::Settings.admin.password
end
end
# Other config stuff should go here
end